Input understanding systems utilize information about the user's personal data and context to consult various knowledge sources that contain information about various entities. This improves abilities of an input understanding system to interpret a user query as well as improve decision making in responding to a user query. As a result, the privacy of the user's information may be transmitted to a service residing outside a client where the information is originally stored. Thus, challenges are presented with respect to preserving confidentiality of a user's private information while leveraging knowledge repositories to increase robustness of an input understanding system. It is with respect to this general technical environment that the present application is directed.